Lifting jack



LIFTING JACK Filed March 7, 1931 2 Sheets-Sheet 1 April 18, 1933. J. F. DONNELLY 1,904,279

LIFTING JACK Filed March 7, 1931 2 Sheets-Sheet 2 Patented Apr. 18, 1933' UNITEDTSTATJELS PATE T OFFICE I JOSEPH F. DONNELLY, OF SOUTH BELL'INGHAM, WASHINGTON Application 11186. March 7 1931. Serial No. 520,901.

'This invention'appertains to lifting acks and has for one of its primary objects'the provision of an extensible lifting jack, whereby the same can be successfully used both for high and low work, without-the necessity of raising'the jack body by means of blocks or the like.

Another important object of my invention is to provide a novel jack embodying an eX- tensible ram, whereby the ack can be placed under a low article and raised twicethe height of anordinary'jack, without having to blocklup the jack'in order to raise the articles to the desired highest position. I A further important object of my nventionis the provision of an extensiblehfting jack embodyinginner and outer telescoping rams,'the inner ram being initially raised bythe jack screw and the outer ram be ng brought into play and raised by the same jack screw after the inner ram has been raised to its extreme height by said ack screw. 8

A further important object of-my'invention is the provision of novel means for coupling the inner and outer rams together, whereby the outer ram will be brought into play automatically by theinner ram, when said inner ram has been initially raised to ts extreme position. v v

A still further object of my invention is to provide an improved lifting jack of the above character, which willbe durable 1 and efficient in use, one that will be simple and easy to manufacture, and one which canbeplaced upon the market at a reasonable cost. With these and otherobjects in lview the inventionconsists in the novel construction,

arrangement and formationof parts, as will be hereinafter more specifically, described, claimed, and illustrated in the accompanying drawings in which drawings: a

Figure 1 is a vertical section through my improved "jack, showing the inner ram raised.

Figure 2 is a horizontal section through Figure 1 taken on the line 22 of Figure 1 looking in the direction of the arrow.

Figure 3 is a similar section taken on the line '33 of Figure 1 looking in the direction of the arrow.

Figure 4; is a similar section taken On the line 4-& of'Figure 1 looking in the di- 5 rection of the arrows;

Figure 5 is a horizontal section taken through the base of the jack on the line 55 of Figure 1 looking in the direction of the arrows.

F'gure 6 is a longitudinal section through the outer ram removed from the jack'body.

casing is provided with a boss 14 disposed directly below the standard 11, and this boss is provided with an axially disposed bearing jack-screw '13. Suitable roller bearings 16 can be interposed between the lower end of the jack screw and the said lower wall of the bearing socket. Keyed or otherwise secured to the ack screw 13 is the driven worm wheel 17; This worm wheel 17 can be driven by any preferred operating mechanism, but I prefer tou'se that-type of operating mechanism illustrated by me in my prior-Patent socket-15, which receives the lower end of the I $21,741,144, issued to me December 31, 1929,

as by this means I am enabled to rotate the jack-screw at different rates of-speed accord: ing to the character and'weight 'of the load being raised. This operating mechanism, as shown, includes a main drive shaft 18 rotatably mounted in suitable bearings carried by the base or housing 12. The main shaft 18 has keyed or otherwise secured thereto the worm 19 which is in constant mesh with the worm wheel .17. The outer end of the shaft 18 is provided witha polygonal head 20 for receiving a suitablerhand crank whereby the shaft 18 may be directly driven for turning the worm wheel.

Disposed in parallel relation to the drive shaft 18 are spaced operating shafts 21 and 22. The outer end of the shaft 21 is provided with a polygonal head 23, whereby a crank can be connected therewith and the shaft 22 is provided with a similar head 24, whereby a hand crank can be connected therewith.

The inner end of the stub shaft 21 is pro vided with a relatively small pinion 25, which meshes with a relatively large gear wheel 26 keyed or otherwise secured to the shaft 18. The inner end of the'shaft 22 has keyed thereto a pinion 27 of greater size than the pinion 25 and this gear or pinion 27 meshes with a gear 28 keyed to the shaft 18 which is of greater size than the gear 26. By this arrangement, it can be seen that the worm wheel 17 can be either driven directly from the shaft 18 or from the shaft 21 or 22, whereby the worm wheel can be readily driven at different rates of speed. 7

y The hollow standard 11 of the jack body is provided at diametrically opposite points with radial screws 30, which are slidably reccived within longitudinal guide grooves 31 formed in the outer face of the outer lifting ram 32. The inner face of the lifting ram 32, at spaced points, such as at quarters, can be provided with longitudinal guide grooves 33, which grooves terminate short of the lower end of the outer ram as do the grooves 31. The upper ends of the grooves 33 can be closed by means of filling plates or plugs 34, which are secured in place by means of screws 35, which extend inwardly beyond the inner face of the outer ram 32 engaging in longitudinal grooves 36 formed in the outer face of the hollow inner lifting ram 37.

v The upper end of the inner lifting ram 37 can be provided with any preferred type of lifting head 38. It is to be noted at this time that the upper ends of the inner grooves 33 of the outer ram 32 terminate in lateral recesses 34, and thus the slots 33 are of a bayonet slot construction.

The extreme lower end of the outer ram 32 has formed thereon or secured thereto in any preferred way a nut body 39, for engagement with the jack screw 13, as will be later described.

I The inner ram 37 is freely slidable within the outer ram 32 and has bearing against the lower end of the same the feed jack nut 40. A ball bearing connection 41 may be had between the lower end of the inner ram and the upper face of the nut 40. The outer face of the nut 40 is provided with radially extending guide lugs 42, which are slidably mounted within the guide grooves 33 formed in the outer ram. This prevents turning of the feed nut 40 relative to the outer ram, and turning of the inner ram relative to the outer ram is prevented by the screws 35. Likewise rotation of the outer ram relative to the hollow standard 11 is prevented by the screws 30.

In operation of my improved jack, upon the turning of the jack screw 13 by any of the shafts 18, 21, or 22, the nut 40 will be fed upwardly on the jackscrewthus raising the inner ram 37 therewith. The raising of the inner ram 37 will permit the raising of the load to the usual or ordinary height, but if the load is to be raised to a relatively great extent the jack screw is further rotated.

This will continue the raising of the outer ram 37 until the lugs 42 of the jack nut 40 reach the upper end of the slots 33 at which time the lugs will ride intolateral-passages 34 of said slots, and the outer ram 32 will be raised. This will lift the threads 'of the nut 39 on the outer ram into engagement with the threads of the jack screw 13 and then the outer ram 32 will be raised carrying the inner ram 37 therewith, it being understood that the lugs 42 are now supported by the walls of the lateral passages 34 of the slots 33; Thus the jack can be raised-to a relatively great height, as the outer ram section can be moved a distance equal to or greater thanthe initial distance traversed by the inner ram 37.

From the foregoing description, it can; be seen that I have provided a novel and simple lifting jack which embodies an extensible lifting ram. g

It is obvious that-my invention is susceptible to various changes and modifications in construction without. departing. from the spirit of the invention or the scope of the appended claim.

What I claim as new is I y r A lifting jack comprising ajack body, a ram including inner and outer telescoping sections, mounted within the body, means for preventing turning movement of the outer section in the body, means for preventing turning movement of the inner section relative to the outer section, a single 'jack screw, means for rotating the jack screw, a feed nut threaded on the jack screw engaging the inner section, the feed nut and outer section having a bayonet slot and pin connection, with the lateral end of the bayonet slot disposed uppermost, whereby the pin of the feed nut will ride into said lateral section of the bayonet slot when the inner section has been raised to an extreme position relative to the outer section, and a feed nut carried by the outer section for engagement with the feed screw upon the raising of the outer section by the first mentioned feed nut; w

In testimony whereof I afiix my signature.

JOSEPH F. DONNE-LLY, 

